An investigation into the stem apex of Syringa vulgaris L. with special reference to the formation of the leaf and leaf procambium.

SUMMARY 1 The stem apex of Syringa vulgaris L. has been examined. 2 The apex can be divided into a tunica and a corpus. 3 . Under another scheme of classification the apex can be divided into a central zone, a flank meristem and a file meristem. 4 . Leaves are initiated in the outer layers of the corpus. 5 . Procambium is produced by longitudinal divisions of cells in the inner layers of the corpus. 6 . The procambium supply of a leaf primordium is continuous at all times. 7 . Vacuolation of the leaf primordium tissues is first abaxial and then adaxial. 8 . The leaf primordium possesses an apical meristem.